Non-toxic nanomaterial for metals extraction

Abstract

Fresh water contamination by heavy metals results from a variety of sources and can be damaging to wildlife, alter landscapes, and impact human health. metals removal form water sources is desirable for improving water quality and preventing adverse effects, but also for metals collection and recycling. Adsorption is a desirable metals extraction technique due to economic feasibility. Nanoscale materials exhibit high surface-area-to-volume ratio that lends to high adsorption and reactivity, making them ideal candidates for adsorptive metals extraction processes. Despite these properties, nanomaterials have elicited safety concerns. The extraordinarily small dimensions of these materials allow them to maneuver biological systems, tissues, and even cells, and combined with high reactivity, this translocation can result in toxic effects. It is therefore imperative that safety of nanomaterials for metals extraction be evaluated in addition to adsorptive properties. The current invention describes nanoparticles composed of magnetite, coated in hydroxyapatite, and functionalized for adsorption with titanium dioxide (TiHAMNPs). This material is safe, provides significant adsorption of metals, and allows efficient collection in magnetic systems.

What is claimed is: 
     
       1. A composition for the extraction of metals from the environment comprising TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs). 
     
     
       2. The composition for the extraction of metals from the environment of  claim 1  wherein the precursors of said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) are comprised of deionized H 2 O, calcium hydroxide (Ca(OH) 2 ), magnetite NPs (Fe 3 O 4 ), and titanium dioxide (TiO 2 ) nanopowder, potassium phosphate (KH 2 PO 4 ). 
     
     
       3. A method for extracting metals from the environment comprising the steps of:
 A. Addition of the TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) of  claim 1  to a liquid that contains an environmental sample to produce a TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture; 
 B. Manipulation of said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture to enable absorption of a metal from said environmental sample to said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs); and 
 C. Collection of said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) containing absorbed said metal. 
 
     
     
       4. The method for extracting metals from the environment of  claim 3 , further comprising the step of synthesizing said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) by wet chemical precipitation methods. 
     
     
       5. The method for extracting metals from the environment of  claim 4 , wherein said wet chemical precipitation methods is comprised of the following steps:
 A. creating a solution by adding an amount of deionized H 2 O and stirring; 
 B. adding an amount of calcium hydroxide (Ca(OH) 2 ) to said deionized H 2 O and stirring until dissolved; 
 C. adding an amount of magnetite NPs (Fe 3 O 4 ) and stirring; 
 D. adding an amount of titanium dioxide (TiO 2 ) nanopowder and stirring; 
 E. dissolving an amount of potassium phosphate (KH 2 PO 4 ) in a separate amount of deionized H 2 O to create a KH 2 PO 4  solution and adding said KH 2 PO 4  solution to said solution to create a mixture; 
 F. reducing the pH of said mixture to approximately 7.5 to create a final solution; 
 G. stirring said final solution; and 
 H. centrifuging said final solution until a pellet of TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) has formed. 
 
     
     
       6. The method for extracting metals from the environment of  claim 3 , wherein said environmental sample is comprised of water. 
     
     
       7. The method for extracting metals from the environment of  claim 3 , wherein said environmental sample is comprised of soil. 
     
     
       8. The method for extracting metals from the environment of  claim 3 , wherein said environmental sample is comprised of biological materials. 
     
     
       9. The method for extracting metals from the environment of  claim 3 , wherein said absorbed metal is comprised of copper. 
     
     
       10. The method for extracting metals from the environment of  claim 3 , wherein said absorbed metal is comprised of a rare earth element. 
     
     
       11. The method for extracting metals from the environment of  claim 3 , wherein the manipulation step of said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture is comprised of any means to increase contact between said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs) and said metal from said environmental sample mixture. 
     
     
       12. The method for extracting metals from the environment of  claim 3 , wherein the manipulation step of said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture is comprised of an inline mixer. 
     
     
       13. The method for extracting metals from the environment of  claim 3 , wherein the collection step is comprised of the TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture travelling through a plurality of magnets. 
     
     
       14. The method for extracting metals from the environment of  claim 3 , wherein the addition, manipulation, and collection steps are contained within an inline pipe system. 
     
     
       15. The method for extracting metals from the environment of  claim 3 , further comprising an induced pressure means, whereby said induced pressure means force said TiO 2 -functionalized hydroxy apatite-coated magnetite nanoparticles (TiHAMNPs)-environmental sample mixture through said addition, manipulation, and collection steps.